Machine for sinking vertical shafts

ABSTRACT

Apparatus for sinking a vertical shaft includes a tubular cutting head. The cutting head is positioned in a guide collar in the earth and is rotated by a rotary drive means to bore the shaft into the ground. A crane and clam shell bucket may be used to remove the spoil generated by this cutting action and to attach additional sections of casing to the cutting head. Means are provided to both urge the cutting head into the ground and to extract it from the shaft.

United States Patent 11 1 1111 3,779,322

Stevens 1 Dec. 18, 1973 [54] MACHINE FOR SINKING VERTICAL 2,076,3794/1937 Marsden 175/171 SHAFTS 3,467,203 9/1969 Johnson 6l/53.5 X [75]Inventor: Richard W. Stevens, Oconornowoc, FOREIGN PATENTS ORAPPLICATIONS Wis, 1,359,022 3/1964 France .1 175/162 I 112,856 1/1969Denmark a 1 175/171 1 Asslgneel Mllwaukee B91191 Manufaclurlng 819,8209/1959 Great Britain 61/53.5

Company, Milwaukee, Wis.

[22] Filed: Man 24, 1972 Primary Examiner-David H. Brown AttorneyAndrus,Sceales, Starke & Sawall [21] Appl. No.: 237,659

[57] ABSTRACT [52] U.S. Cl. 175/162, 61/41 R, 175/171, Apparatus forsinking a vertical shaft includes a tubu- 175/220, 175/203 lar cuttinghead. The cutting head is positioned in a [51] Int. Cl. 1521b 3/02,1321b 19/08, E21 11/00 guide collar in the earth and is rotated by arotary [581 Field of Search 61/41, 53.5; iv m ns to ore the shaft intothe ground. A crane 175/162, 171, 203, 220 and clam shell bucket may beused to remove the spoil generated by this cutting action and to attachaddi- [56] Refe n e Cit d tional sections of casing to the cutting head.Means UNITED STATES PATENTS are provided to both urge the cutting headinto the 1,847,814 3/1932 Byrne 61/41 R ground and to extract from theShaft 1,894,206 1/1933 Talbot 61/41 R 20 Claims, 7 Drawing Figures 3/ I11 1 llll|ll111l [ll Z H ill 1 il 53 I11. 1111-1 5 |l| ||i ll 55111111111 3: 1- l 1 ILZ l:ll]'1||||| I'll 9 11i 11 1 if /g V & K

MACHINE FOR SINKING VERTICAL SHAFTS BACKGROUND OF THE INVENTION 1. Fieldof the Invention The present invention relates to earth workingequipment for driving tubes or casings into the ground in a generallyvertical direction.

2. Description of the Prior Art It is often desired to sink verticalshafts of considerable diameter, for example, 7 to 24 feet, into theearth. A typical application is the provision of work shafts inconjunction with the construction of subterranean tunnels. Such work'shafts permit the provision and removal of equipment, and the dischargeof muck and other debris from the tunnel during construction. Similarly,man holes permit the entry and egress of workmen, both during and afterconstruction. Vertical shafts, or drop sewers, are also required betweenhorizontal sewers located at different levels. The depth of verticalshafts of the foregoing types may typically range from 60 to 100 feet upto a maximum of 200 feet or more.

In the past, vertical shafts have been constructed by conventional earthworking techniques. A hole is dug in the ground having a circumferenceapproximately the same as that intended for the vertical shaft. Thedepth of the hole is determined by the subsidence characteristics of thesoil. The hole is then lined with wood, concrete, or metal walls, afterwhich the hole is dug deeper, the wall construction continued, and so onuntil the shaft has been extended to the desired depth.

It will be appreciated that these conventional techniques are both timeconsuming and expensive, requiring large amounts of equipment and largenumbers of men. Further, the presence of workmen is required in the holeduring the sinking of the shaft. The risk of injury is quite high.Insurance, and other similar costs, are correspondingly high.

In the case of an access or work shaft, it may subsequently be desiredto remove'the shaft walls after the subterranean work has beencompleted. For example, upon the completion of a tunnel construction,concrete forms may be placed in the access shaft and a small manholeshaft poured. The access shaft walls are then removed and the shaftbackfilled around the poured manhole casing. In other instances, thebottom of the access shaft may be sealed, the walls removed and theentire shaft refilled. Conventional earth working techniques andequipment also render this aspect of vertical shaft constructionexpensive, time consuming, and hazardous because of the necessity ofplacing men in the shaft, and for other reasons.

SUMMARY OF THE PRESENT INVENTION It is, therefore, the object of thepresent invention to provide a machine for rapidly, inexpensively, andsafely sinking vertical shafts.

The machine of the present invention is capable of sinking shafts oflarge diameter. The machine is simple in construction, utilizing themachines own weight to assist a rotary cutter in boring the shaft. Asthe depth of the shaft increases, the weight of the machine increasesdue to the attachment of additional sections of shaft lining casing,thereby increasing the effectiveness of the boring action of themachine. The machine may employ an oscillatory rotary cutting actionwhich facilitates maintaining the plumb and line of the vertical shaft.

The machine is operable on a continuous basis with a small crew. It maybe particularly noted that the machine does not require the presence ofworkmen in the shaft during either the sinking of the shaft or removalof the shaft lining casing, thereby providing a high degree of safety toits operation. The machine is portable, facilitating movement of theapparatus from one work site to another.

Briefly, the vertical shaft sinking machine of the present inventionincludes a guide collar locatable in the earth along the axis of theshaft. A tubular cutting head having a cutting bit on the lower edgethereof is rotatably mounted in the guide collar. Extensible means, suchas a plurality of hydraulic cylinders coupled between the guide collarand the exterior of the cutting head, are provided for rotating thecutting head in the guide collar to sink the shaft. Because the rotarydrive means is coupled to the outside of the cutting head, the interiorof the cutting head is free from obstruction, allowing removal of thespoil during operation of the cutting head.

As the sinking of the shaft progresses, additional sections of casingare attached to the cutting head. The machine also includes means forretracting the casings through the guide collar.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partially cut away view ofthe machine for sinking vertical shafts of the present invention.

FIG. 2 is a top view of the vertical shaft sinking machine taken alongline 2-2 of FIG. 1, said view also being partially cut away to revealcertain details of the machines construction.

FIG. 3 is an enlarged partial view of clamping elements of the machine,said view being partially cut away to reveal the details of theelements.

FIG. 4 is a partial plan view of a portion of the machine showing meansby which the rotary drive means for the machine may be adjustablypositioned on the guide collar.

FIG. 5 is a partial elevational view of the machine of the presentinvention showing means for extracting portions of the machine from theshaft.

FIG. 6 is a cross sectional view taken along the line 6-6 of FIG. 5showing the use of portions of the machine to assist in affixingadditional sections of casing to the cutting head of the machine.

FIG. 7 is an elevational view showing the use of a crane in conjunctionwith the machine of the present invention. The crane may be used toposition additional sections of easing, as shown in FIG. 7; to removespoil from the interior of the machine; or to position portions of, orassemble, the machine.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention employscutting head 12 to sink the vertical shaft. Cutting head 12 is comprisedof a section of casing or tubing 14, similar to that used to line thevertical shaft as it is sunk. An annular cutting bit 16 may incorporateany commonly available rotary cutter construction suitable for the typeof soil into which the vertical shaft is being sunk. As will hereinafterbe noted, it is desirable that cutting bit 16 afford a penetratingaction in either direction of rotaton. Serrating the lower edge ofcutting bit 16, as shown in FIG. 1, to form teeth 18 has been found toprovide a cutting bit of satisfactory construction.

Guide collar 20 is positioned in the earth along the bore of thevertical shaft to form a journal for the rotation of cutting head 12.Guide collar 20 includes tubular liner 22. In order to both provideguidance and permit the necessary rotation of the cutting head 12, ithas been found desirable to make the diameter of tubular liner 22 largerthan the diameter of cutting head 12 by an amount necessary to achievethese objectives. The difference in diameters may typically be 1 inchbut will vary depending on the diameters of cutting head 12, liner 22,and other factors.

Tubular liner 22 in cast in concrete pad 24. Tubular liner 22 may beprovided with flanges 26 to secure the liner in concrete pad 24 againstthe circumferential forces exerted during the rotation of cutting head12. Circumferential reinforcing bars 28 may be inserted in the concretepad to reinforce the pad.

To lubricate casing 12 in its engagement with liner 22 and with theearth, a lubricating slurry of bentonite, or the like, may be provided.For injecting the slurry, it has been found desirable to mount aplurality of circumferentially spaced pipes 30 along the inside ofcasing 14 of cutting head 12. The pipes empty on the exterior of thecutting head 12, above cutting bit 16, as shown in FIG. 1. The upperends of pipes 30 contain flexible hoses 31 and couplings 33 toaccommodate the movement of cutting head 12. Couplings 33 alsofacilitate the attachment of additional sections of casing to cuttinghead 12, as hereinafter described.

One or more pipes 32 may be provided in concrete pad 24 on the peripheryof tubular liner 22 so that the presence and amount of slurry may beascertained either by the discharge from the upper end of pipes 32 or byan appropriate instrument located in the pipe.

To provide rotation to cutting head 12 in guide collar 20 a clampingring having a rotary drive means associated therewith engages theportion of cutting head 12 which extends above guide collar 20. Clampingring 40, hereinafter sometimes called the lower clamping ring, rests onconcrete pad 24 and the concrete pad may be provided with wear orbearing plate 41 to reduce the friction and wear occurring when clampingring is rotated, as hereinafter described. Clamping ring 40, which maybe of hollow box-like construction, as shown in FIG. 1, is comprised oftwo semi-circular halves 40a and 40b pivotally joined at hinge 42. Ring40 is clamped on cutting head 12 by toggle mechanisms 44a and 44blocated diametrically opposite hinge 42. The toggle mechanisms are shownin detail in FIG. 3. In as much as the toggle mechanisms are similar,only one such mechanism 44a is described in detail.

Toggle mechanism 44a includes bar 46 having one end connected to pin 48in ring half 40b. The other end of bar 48 is pivotally connected totoggle 50 which in turn is pivotally mounted on ring half 40a by pin 51.The arm 52 of toggle 50 is connected to one end of hydraulic cylindrical54, the other end of which is connected to ring half 40a. Togglemechanism 44a is preferably mounted inside the ring and an opening isprovided in the outer wall 56 of ring half 40a for toggle arm 52 andhydraulic cylinder 54.

The second toggle mechanism 44b may be positioned below toggle mechanism44a. One end of the bar of toggle mechanism 44b is connected to ringhalf 40a and toggle 58 and hydraulic cylinder 60 are mounted on ringhalf 40b.

By extending the pistons of hydraulic cylinders 54 and 60, toggles 50and 58 are pivoted to draw ring halves 40a and 40b together and clamplower clamping ring 40 on casing 14 of cutting head 12. By retractingthe pistons of hydraulic cylinders 54 and 60, toggles 50 and 58 arepivoted to push ring halves 40a and 40b apart and release lower clampingring 40 from cutting head 12.

Rotation of lower clamping ring 40 and cutting head 12 may be providedby an extensible means having one or more extensible elements. This maytypically comprise two pairs of opposed hydraulic cylinders havingextensible rams. Hydraulic cylinders 62 and 64 each have one end of thecylinder body anchored in concrete pad 24 and one end of the ramconnected to a common journal 59 on lower clamping ring 40. Similarly,hydraulic cylinders 55 and 58 each have one end of the cylinder bodyanchored in concrete pad 24 and one end of the ram connected to a commonjournal 61 on ring 40. The journal 59 for hydraulic cylinders 62 and 64may be diametrically opposite the journal 61 for hydraulic cylinders 66and 68 on lower clamping ring 40.

The hydraulic cylinders are joined to concrete pad 24 in a manner whichallows horizontal adjustment of the hydraulic cylinder ends, therebypermitting positional correction of the vertical shaft. Such positionalcorrections include corrections to line which insure that the machineand the shaft are located at the desired location on the ground, forexample, with the axis of the shaft in alignment with the surveyedcenter of the shaft. The horizontal correction of the cylinders may alsoassist in corrections to plumb which insure that the machine, and hencethe shaft sunk thereby, has the desired degree of verticality.

The afiixation of the hydraulic cylinders to concrete pad 24 may best beseen in FIG. 4. A plurality of threaded rods 63 are embedded in concretepad 24 adjacent the ends of each of the cylinders. FIG. 4 shows the useof four such rods in connection with cylinder 62. Plate 65 having fourslots 67 mating with threaded rods 63 is placed over the threaded rodsand retained thereon by nuts 69. Gudgeon 71 mounted on the end ofhydraulic cylinder 62 fits over anchor post 73 mounted on plate 65 tojoin the hydraulic cylinder to the concrete pad.

The ends of hydraulic cylinders 64, 66, and 68 are anchored in concretepad 24 in a manner similar to that described in detail in connectionwith hydraulic cylinder 62 as shown in FIG. 2. By loosening nuts 69 onthreaded rods 63, the position of the hydraulic cylinders on concreteanchor pad 24 and hence the position of cutting head 12 in tubular liner22 may be altered to correct locational or other errors.

By extending the rams of hydraulic cylinders 62 and 68, lower clampingring 40 and cutting head 12 are rotated in the counter-clockwisedirection when viewed as in FIG. 2. By extending the rams of hydrauliccylinders 64 and 66, lower clamping ring 40 and cutting head 12 arerotated in the clockwise direction. In some instances, it may bedesirable to use less than four cylinders. For example, only one ofcylinders 62 and 64 and one of cylinders 66 and 68 may be utilized or,in some cases, only a single cylinder or one pair of cylinders 62 and 64or 66 and 68 may be employed. The hydraulic cylinders may be single ordouble acting, as desired.

A second, or upper, clamping ring 70, mounted above clamping ring 40,also engages the portion of cutting head casing 14 which extends aboveguide collar 20, as shown in FIG. 1. Upper clamping ring 70 may besimilar in construction to lower clamping ring 40 to include twosemi-circular halves 70a and 70b of hollow box-like construction,pivotally joined at hinge 72. Upper clamping ring 70 is clamped oncutting head casing 14 by toggle mechanisms 74a and 74b locateddiametrically opposite hinge 72 and operable by hydraulic cylinders 73and 75, respectively. Toggle mechanisms 74a and 74b may be similar inconstruction and opera- 1 tion to toggle mechanisms 44a and 44b utilizedin connection with lower clamping ring 40.

Upper clamping ring 70 is separated from lower clamping ring 40 by aplurality of circumferentially spaced hydraulic jacks 76, the housingsof which are affixed to lower clamping ring 40 and the terms 78 of whichabut the underside of upper clamping ring 70. This construction may beseen in FIGS. 5 and 6. Also, as shown most clearly in FIGS. 5 and 6, aplurality of peripheral slots 80 are provided in the walls of upperclamping ring 70. No rotary drive means is coupled to upper clampingring 70.

Cutting head 12 is urged into contact with the earth to obtain thedesired cutting action by the weight of cutting head 12. Because of theheavy construction of cutting head 12, clamping rings 40 and 70, etc.,the weight of this apparatus will, in many cases, be fully sufficient asa vertical driving force. In other cases, the intrinsic weight ofcutting head 12, clamping rings 40 and 70, etc., may be augmented withan additional circular weight 34 placed on the upper edge of cuttinghead casing 14 as by crane 82 shown in FIG. 7. A notch 36 is provided inweight 34 to retain the weight on the cutting head casing. It will beappreciated that as the sinking of the shaft progresses and additionalsections of casing are affixed to cutting head casing 14, the weight ofthe machine increases, increasing the vertical force and theeffectiveness of the machines cutting action.

A power supply, not shown, is provided to energize the various elementsof shaft sinking machine 10. The power supply includes a hydraulicpressure system with a source of hydraulic pressure such as aconventional hydraulic pump. The hydraulic pressure system is used toextend and retract rotation producing hydraulic cylinders 62, 64, 66 and68 and to extend and retract hydraulic lift jacks 76. The operation ofthese elements is coordinated with the operation of hydraulic cylinders54 and 60 and 73 and 75 in the clamping ring toggle mechanisms 44 and74. A slurry pump, coupled to hoses 31, is also provided.

Vertical shaft sinking machine also includes a means to remove the spoilgenerated by the sinking of the vertical shaft. This means may comprisethe crane 82 shown in FIG. 7, positioned adjacent concrete pad 24 andhaving clam shell bucket 84 or other scoop means which may be lowereddown the vertical shaft to pick up the spoil and then raised out of theshaft to remove it. Crane 82 may also be used to assemble ma-.

chine 10, to apply and remove weight 34, and to position additionalsections of casing for attachment to cutting head 12.

' hydraulic cylinders 62 through 68 may be appropriately positionedprior to the pouring of the concrete pad.

Clamping ring 40 is hoisted over the portions of cutting head casing 14extending above concrete pad 24, as by means of crane 82. With hydrauliccylinders 54 and 60 retracted to move toggle mechanisms 44a and 44b tothe unclamped position the ring is lowered over cutting head 12 to reston wear plate 41. One end of each of hydraulic cylinders 62 through 68is anchored on rods 63 embedded in concrete pad 24 in the manner shownin FIG. 4 and described above. The other ends of the hydraulic cylindersare joined to journals 59 and 61 on lower clamping ring 40. Varioushydraulic cylinders associated with lower clamping ring 40 are connectedto the source of hydraulic pressure and hydraulic cylinders 54 and 60are extended to clamp the ring on the cutting head casing. The rams 78of hydraulic jacks 76 are also extended. Pipes 31 are connected to theslurry pump.

Upper clamping ring 70 may then be placed on cutting head casing 14 byprocedures similar to that employed in conjunction with lower clampingring 40 to rest on the extended rams 78 ofjacks 76. Hydraulic cylinders73 and 75 of toggle mechanisms 74a and 74b are then connected to thehydraulic pressure system and the cylinders are extended to clamp ring70 on cutting head casing 14. Thereafter, the rams 78 of hydraulic jack76 may be retracted to leave upper clamping ring 70 positioned abovelower clamping ring 40 on cutting head casing 14.

Weight 34 may then be placed on the upper edge of cutting head 12 as bymeans of crane 82.

The slurry pump is started to provide a lubricating slurry around casing14.

Hydraulic cylinders 62 through 68 are then operated to rotate lowerclamping ring 40 and cutting head 12. Two modes of periodic rotatingaction may be provided a bidirectional, oscillating mode and aunidirectional mode. The type of rotating action employed is selected inaccordance with the type of soil through which the shaft is being sunk,the construction of cutting bit 16, etc. To oscillate cutting head 12first in one direction and then in the other, hydraulic cylinders 62through 68 are initially extended to move cutting head 12 in the counterclockwise direction. Thereafter hydraulic cylinders 64 and 66 areextended to move cutting head 12 clockwise. Lower clamping ring 40 rideson wear plate 41 during rotation.

In a unidirectional rotation operating mode, one pair of the hydrauliccylinders, for example, hydraulic cylinders 62 and 68 are initiallyextended to rotate cutting head 12 in the counter clockwise direction.Hydraulic cylinders 54 and 60 are then retracted to loosen lowerclamping ring 40 on cutting head 12. Hydraulic cylinders 64 and 66 areextended to rotate lower clamping ring 40, but not cutting head 12, inthe clockwise direction. Hydraulic cylinders 54 and 60 are then extendedto reclamp lower clamping ring 40 on cutting head 12,

and hydraulic cylinders 62 and 68 are re-extended to continue thecounter clockwise rotation of cutting head 12. By an analogous operationand coordination of hydraulic cylinders 62 through 68 and hydrauliccylinders 54 and 60 in toggle mechanisms 44a and 44b, clockwise rotationof cutting head 12 may be produced.

While the oscillatory mode of rotary action is presently preferred,since the alternating cutting directions tend to prevent displacement ofthe axis of the shaft from its desired location, machine 10 of thepresent invention also facilitates use of a constant rotary cuttingdirection by overcoming difficulties previously encountered with thistechnique. With a constant or unidirectional rotary cutting direction,the torque applied to cutting head 12 as the shaft is sunk has, in thepast, tended to displace the axis from its intended course. However,through the use of guide collar 20, the machine of the present inventionpermits a unidirectional rotary cutting direction while at the same timeminimizing or eliminating the tendency for the shaft to drift offcourse.

After several oscillatory or unidirectional incremental rotary motionsof cutting head 12, hydraulic cylinders 54 and 60 are retracted toloosen lower clamping ring 40 and allow cutting head 12 to descend,driven by its weight, the weight of clamping ring 70, and the weight ofweight 34, if applied. Hydraulic cylinders 54 and 60 are then extendedto reclamp lower clamping ring 40 and the rotation of cutting head 12 isresumed to recommence sinking the vertical shaft. The spoil whichaccumulates inside the cutting head as a result of the cutting action ofcutting bit 16 and the descent of cutting head 12 is removed by clamshell bucket 84. Spoil removal may be carried out while cutting head 12is being rotated, if desired.

As cutting head 12 descends, upper clamping ring 70 which is clamped oncasing 14, approaches the upper ends of rams 78 of hydraulic jacks 76located on lower clamping ring 40. When this occurs, the rotation ofcutting head 12 is stopped. The rams 78 of hydraulic jacks 76 areextended into contact with the lower surface of upper clamping ring 70.Hydraulic cylinders 73 and 75 of toggle mechanisms 74a and 74b are thenretracted to release upper clamping ring 70 from cutting head casing 14and rams 78 operated to their full extension to raise upper clampingring 70 along cutting head casing 14. Hydraulic cylinders 73 and 75 areextended to reclamp upper clamping ring 70 on cutting head casing 14 andrams 78 retracted. The rotary operation of vertical shaft sinkingmachine 10 then recommences to resume sinking the vertical shaft. Eachtime upper clamping ring 70 approaches lower clamping ring 40, the abovedescribed operation is repeated.

When cutting head 12 has sunk so that upper clamping ring 70 can nolonger be raised along casing 14 of cutting head 12, an additionalsection of easing must be added. Weight 34, if in use, is removed andslurry hoses 31 disconnected. Lower clamping ring 40 remains clamped tocutting head 12 as the rams 78 of hydraulic jacks 76 are brought intocontact with the lower surface clamping ring 70. Upper clamping ring 70is then loosened. Hydraulic jacks 76 are operated to extend rams 78 toposition upper clamping ring 70 so that a portion of its extends beyondthe upper edge of casing 14. A new section of easing 14a is then raisedover cutting head 12, as shown in FIG. 7, and lowered into the exposedportion of ring 70. Clamping ring is tightened to hold casings 14 and14a together and to insure the concentricity of the two sections. Thesections of easing are then tack welded through slots 80, as shown inFIGS. 5 and 6. Thereafter upper clamping ring 70 is unclamped, rams 78retracted to lower the ring and expose the casing joint, the upperclamping ring 70 reclamped. The casings are welded together around theirentire circumference, weight 34, if needed, replaced, slurry hoses 31reconnected and the operation of shaft sinking machine 10 resumed tofurther sink the shaft.

Depending on the depth of the shaft, the size and thickness of thecasing, etc., it may be necessary to provide vertically spacedreinforcing rings on the inner periphery of the shaft casing. Theserings can be installed in the casings prior to use or can be positionedas the sinking of the shaft progresses.

In the event the vertical shaft drifts off line or out of plumb, theseerrors may be corrected by altering the position of hydraulic cylinders62 through 68 adjusting the position of anchor plates 65 on rods 63 inthe manner described above, and/or by partially extracting cutting head12 from the shaft, correcting the error, and restarting the cuttinghead. This latter operation may be accomplished in the following manner.When upper clamping ring 70 approaches the upper ends of rams 78 ofhydraulic jacks 76, the rotation of cutting head 12 is stopped. Lowerclamping ring 70 is unclamped from cutting head 12. Rarns 78 ofhydraulic jacks 76 are then extended to full extension. In as much asupper clamping ring 70 remains clamped to cutting head casing 14, theextension of rams 78 raises cutting head 12 with upper clamping ring 70.Lower clamping ring 40 is then reclamped on casing 14 of cutting head 12to retain cutting head 12 in the extracted position, and the hydraulicjacks are retracted. The position of anchor plates 65 may be adjusted orother corrections may be made. It will be appreciated that only selectedones of hydraulic jacks 76 may be extended, for example, to raise oneside of cutting head 12 to take corrective action. The rotation ofcutting head 12 is then resumed to recommence sinking the verticalshaft.

In the event a single extension of hydraulic jacks 76 does not providethe desired amount of extraction, upper clamping ring 70 may beunclamped prior to the retraction of hydraulic jacks 76 for loweringalong casing 14 of cutting head 12 as the hydraulic jacks are retracted.Upper clamping ring 70 is reclamped in the lower position, lowerclamping ring 40 unclamped, and hydraulic jacks 76 extended to continuethe extraction of cutting head 12.

In the instance in which vertical shaft casing 14 is to be removed, theabove described extractive operation is repeated until the casing iscompletely removed from the shaft. In many cases, the vertical shaftwill have joined a subterranean horizontal tunnel through which cuttingbit 16 will have been removed. If not, the cutting bit 16 isdisassembled. Once this has been accomplished, workmen need not enterthe shaft during the removal of the shaft casing. The extraction of theshaft casing is carried out through the coordinated operation of lowerclamping ring 40, upper clamping ring 70 and hydraulic jacks 76. Ifnecessary, the shaft casing may be rotated during extraction. As thesections of welded casing emerge from the shaft, they are cut apart withtorch or other means. When the casings have been completely removed, theshaft is backfilled. Concrete pad 24 may be broken up or left as part ofthe surface structure.

It will be appreciated that the hydraulic pressure system for verticalshaft sinking machine may include means such as limit switches, solenoidoperated valves, and the like, to render all or portions of theoperation of machine 10 automatic or semi-automatic. For example, theoscillatory rotation of cutting head 12 may be rendered automatic bycoordinating the operation of hydraulic cylinders 62 and 68 andhydraulic cylinders 64 and 66. To provide automatic unidirectionalrotary motion, the operation of these hydraulic cylinders may becoordinated with the operation of hydraulic cylinders 54 and 60 intoggle machanisms 44a and 44b which clamp and unclamp lower clampingring 40. Similarly, by coordinating the clamping and unclamping of lowerclamping ring 40 and upper clamping ring 70 and the extension andretraction of hydraulic jacks 76, the control of the vertical movementof the casings may be rendered automatic.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim:

1. Earth working apparatus for sinking a shaft easing into the earth,said apparatus comprising:

guide collar means extendible below the surface of the earth at theplace of sinking the shaft and suitable for restraining engagement withthe earth, said guide collar means having an exposed upper surface;

a tubular cutting head extending through, and rotatably journalled in,said guide collar means, said head having a cutting bit on the loweredge thereof;

a clamping ring resting on said exposed upper surface of said collarmeans and rotatable with respect to said guide collar means, saidclamping ring being engageable with the exterior periphery of a portionof the cutting head extending above said guide collar means for rotatingthe cutting head while preventing axial moyement of the cutting headwith respect to the guide collar when engaged; and

drive means mbunted on the upper surface of said guide collar means andcoupled between said clamping ring and said guide collar means forperiodically rotating said clamping ring and said cutting head in saidguide collar means.

2. The earth working apparatus according to claim 1 wherein saidclamping ring includes hinged circumferential segments and a clampingcoupling means for pivoting the segments between a closed, cutting headengaging condition, and an open, non engaging condition.

3. The earth working apparatus according to claim 1 wherein said tubularcutting head has an upper edge adapted to receive a downwardly exertedforce and said apparatus includes a weight positioned on said upperedge.

4. The earth working apparatus according to claim 1 including means forremoving spoil from the interior of the cutting head.

5. The earth working apparatus according to claim 1 wherein said cuttinghead has additional sections of easing attached thereto as the sinkingof the shaft progresses.

6. The earth working apparatus according to claim 5 including means forerecting said casing sections over said cutting head in verticalalignment therewith for attachment to said cutting head.

7. The earth working apparatus according to claim 1 further includingmeans for supplying lubricant to said cutting head for facilitating thesinking of the shaft.

8. The earth working apparatus according to claim 7 wherein saidlubricant supplying means comprises pipes mounted in the cutting headand opening adjacent said cutting bit.

9. The earth working apparatus according to claim 1 wherein said drivemeans comprises extensible means anchored on the upper surface of saidguide collar means and tangetially coupled to said clamping ring forproviding oscillatory rotation to the latter.

10. The earth working apparatus according to claim 9 wherein saidextensible means comprises at least one extensible element anchored insaid guide collar means and tangentially coupled to said clamping ring.

11. The earth working apparatus according to claim 10 wherein saidextensible element comprises a hydraulic cylinder.

12. The earth working apparatus according to claim 10 wherein saidtubular cutting head is radially movable within said guide collar meansand said extensible means is adjustably anchored on said guide means forlocating said cutting head within said guide collar means.

13. The earth working apparatus according to claim 10 wherein saidextensible means comprises a plurality of extensible elements anchoredin said guide collar means and tangentially coupled to said clampingring.

14. The earth working apparatus according to claim 13 wherein saidextensible means includes first and second pairs of opposed extensibleelements coupled for reciprocal operation, said pairs of extensibleelements having a reciprocally movable portions coupled to said clampingring for providing oscillatory rotation to said clamping ring.

15. The earth working apparatus according to claim 9 wherein saidclamping ring is selectively engageable with said cutting head, theselective engagement of said clamping ring with said cutting headpermitting unidi rectional rotation of the latter from the oscillatoryrotation of the former.

16. The earth working apparatus according to claim 15 including an upperring mounted on said cutting head above said clamping ring andselectively engageable with said cutting head, and said apparatusincludes means interposed between said upper ring and said clamping ringfor spacedly positioning said upper ring with respect to said clampingring.

17. The earth working apparatus according to claim 16 wherein said upperring includes hinged circumferential segments and a coupling means forpivoting said circumferential portions between a closed, cutting headengaging condition and an open non engaging condition.

18. The earth working apparatus according to claim 16 wherein said upperring includes one or more peripheral slots to permit access to theinterior thereof.

19. The earth working apparatus according to claim 16 wherein said meansfor spacedly positioning said upper ring comprises a plurality ofcircumferentially spaced, extensible means mounted on one of said upperring and said clamping ring and coaxially abutting the other of saidupper ring and clamping ring.

20. The earth working apparatus according to claim 19 wherein saidextensible means comprises a plurality of hydraulic jacks.

1. Earth working apparatus for sinking a shaft casing into the earth,said apparatus comprising: guide collar means extendible below thesurface of the earth at the place of sinking the shaft and suitable forrestraining engagement with the earth, said guide collar means having anexposed upper surface; a tubular cutting head extending through, androtatably journalled in, said guide collar means, said head having acutting bit on the lower edge thereof; a clamping ring resting on saidexposed upper surface of said collar means and rotatable with respect tosaid guide collar means, said clamping ring being engageable with theexterior periphery of a portion of the cutting head extending above saidguide collar means for rotating the cutting head while preventing axialmovement of the cutting head with respect to the guide collar whenengaged; and drive means mounted on the upper surface of said guidecollar means and coupled between said clamping ring and said guidecollar means for periodically rotating said clamping ring and saidcutting head in said guide collar means.
 2. The earth working apparatusaccording to claim 1 wherein said clamping ring includes hingedcircumferential segments and a clamping coupling means for pivoting thesegments between a closed, cutting head engaging condition, and an open,non engaging condition.
 3. The earth working apparatus according toclaim 1 wherein said tubular cutting head has an upper edge adapted toreceive a downwardly exerted force and said apparatus includes a weightpositioned on said upper edge.
 4. The earth working apparatus accordingto claim 1 including means for removing spoil from the interior of thecutting head.
 5. The earth working apparatus according to claim 1wherein said cutting head has additional sections of casing attachedthereto as the sinking of the shaft progresses.
 6. The earth workingapparatus according to claim 5 including means for erecting said casingsections over said cutting head in vertical alignment therewith forattachment to said cutting head.
 7. The eaRth working apparatusaccording to claim 1 further including means for supplying lubricant tosaid cutting head for facilitating the sinking of the shaft.
 8. Theearth working apparatus according to claim 7 wherein said lubricantsupplying means comprises pipes mounted in the cutting head and openingadjacent said cutting bit.
 9. The earth working apparatus according toclaim 1 wherein said drive means comprises extensible means anchored onthe upper surface of said guide collar means and tangetially coupled tosaid clamping ring for providing oscillatory rotation to the latter. 10.The earth working apparatus according to claim 9 wherein said extensiblemeans comprises at least one extensible element anchored in said guidecollar means and tangentially coupled to said clamping ring.
 11. Theearth working apparatus according to claim 10 wherein said extensibleelement comprises a hydraulic cylinder.
 12. The earth working apparatusaccording to claim 10 wherein said tubular cutting head is radiallymovable within said guide collar means and said extensible means isadjustably anchored on said guide means for locating said cutting headwithin said guide collar means.
 13. The earth working apparatusaccording to claim 10 wherein said extensible means comprises aplurality of extensible elements anchored in said guide collar means andtangentially coupled to said clamping ring.
 14. The earth workingapparatus according to claim 13 wherein said extensible means includesfirst and second pairs of opposed extensible elements coupled forreciprocal operation, said pairs of extensible elements having areciprocally movable portions coupled to said clamping ring forproviding oscillatory rotation to said clamping ring.
 15. The earthworking apparatus according to claim 9 wherein said clamping ring isselectively engageable with said cutting head, the selective engagementof said clamping ring with said cutting head permitting unidirectionalrotation of the latter from the oscillatory rotation of the former. 16.The earth working apparatus according to claim 15 including an upperring mounted on said cutting head above said clamping ring andselectively engageable with said cutting head, and said apparatusincludes means interposed between said upper ring and said clamping ringfor spacedly positioning said upper ring with respect to said clampingring.
 17. The earth working apparatus according to claim 16 wherein saidupper ring includes hinged circumferential segments and a coupling meansfor pivoting said circumferential portions between a closed, cuttinghead engaging condition and an open non engaging condition.
 18. Theearth working apparatus according to claim 16 wherein said upper ringincludes one or more peripheral slots to permit access to the interiorthereof.
 19. The earth working apparatus according to claim 16 whereinsaid means for spacedly positioning said upper ring comprises aplurality of circumferentially spaced, extensible means mounted on oneof said upper ring and said clamping ring and coaxially abutting theother of said upper ring and clamping ring.
 20. The earth workingapparatus according to claim 19 wherein said extensible means comprisesa plurality of hydraulic jacks.